As is known in the art, large host computers and servers (collectively referred to herein as “host computer/servers”) require large capacity data storage systems. These large computer/servers generally include data processors, which perform many operations on data introduced to the host computer/server through peripherals including the data storage system. The results of these operations are output to peripherals, including the storage system.
One type of data storage system is a magnetic disk storage system. Here a bank of disk drives and the host computer/server are coupled together through an interface. The interface includes “front end” or host computer/server controllers (or directors) and “back-end” or disk controllers (or directors). The interface operates the controllers (or directors) in such a way that they are transparent to the host computer/server. That is, data is stored in, and retrieved from, the bank of disk drives in such a way that the host computer/server merely thinks it is operating with its own local disk drive. One such system is described in U.S. Pat. No. 7,124,245, (“the '245 patent”) entitled “Data Storage System Having Cache Memory Manager with Packet Switching Network”, inventors Walton et al., issued Oct. 17, 2006, and assigned to the same assignee as the present invention, which patent is incorporated herein by reference in its entirety.
In such a system, each microprocessor 329 in each of the front end directors 350 is always at full power, in one example at 80 W, in order to enable the system to provide desired storage response times to satisfy unplanned peak workloads. The processor architecture is designed to enable the system to be able to handle peak loads at all times so that response times consistently meet application requirements. However, during low workload times, the processors remain operating at full power, resulting in unnecessary power consumption.